Description Usage Arguments Value See Also
Extract elements from Rd containers
These functions can be used to extract or subset elements of
Rd lists, either bare Rd
containers or Rd_tag
objects.
The [[
operator performs classification of output.
Rd_get_element
acts as [[
but will also accept tags to
search for. The [
operator wraps
Rd_subset
, respectively.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
x |
Either an |
... |
Must be empty. |
drop |
For matrices and arrays. If |
i |
indices specifying elements to extract or replace. Indices are
For When indexing arrays by An index value of |
Rd_get_element
and [[
:
the return value is not necessarily an Rd.
The class of the element returned will
inferred if it does not have a class.
Lists will be classed as Rd
unless the Rd_tag
attribute
is set in which case a Rd_tag
will be returned
Rd_subset
and [
:
will always return a value of the same class as is given.
Even if what is returned is an empty list, an empty list with
the Rd_tag
attribute set is valid, and denotes a tag without
any content such as the "\item" tag.
base::Extract
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